1. Field of the Invention
The present invention relates to a stabilizer which is used for vehicles such as motor vehicles. More particularly, the present invention relates to a technique for preventing the stabilizer from sideslipping on the vehicle and for facilitating mounting operations for the stabilizer on the vehicle.
2. Description of the Related Art
Conventionally, stabilizers have been used as spring members for preventing vehicles from rolling when running at a curve. A conventional stabilizer is shown in FIG. 7. The stabilizer is equipped with a torsion portion 1 which extends in the width direction of a vehicle and arm portions 2 which extend from both side end portions of the torsion portion 1 in a forward direction of the vehicle. Both side end portions of the torsion portion 1 are mounted to a body of the vehicle. Leading end portions of the arm portions 2 are mounted to wheels of the vehicle. In this case, bushes 3 made of rubber are mounted around the torsion portion 1, and the torsion portion 1 is mounted to the body of the vehicle via the bushes 3.
When a motor vehicle with the above stabilizer runs at a curve, the body of the motor vehicle rolls to the outside of the curve due to centrifugal force. Wheels of the motor vehicle contact the road surface, and displacement of the respective arm portions 2 is thereby generated in directions opposite to each other, and a torsional moment is generated in the torsion portion 1. Elastic force which resists the torsional force is generated in the torsion portion 1, and the body of the motor vehicle is restored to a horizontal state. In this case, when the body rolls, the stabilizer moves in the width direction of the motor vehicle. As a result, the stabilizer interferes with other parts of the vehicle.
Therefore, in a conventional method, as shown in FIG. 7, stoppers 4 are provided at the inside or the outside of the bushes 3 which are around the torsion portion 1 so as to prevent the stabilizer from sideslipping. The stopper 4 is composed of a ring which is made of metal, and is fixed by welding or caulking on the torsion portion 1. For example, the stopper 4 is disclosed in Japanese Patent Unexamined Application Publication No. 11-210713.
The distance between bushes is generally about 500 to 1000 mm, which differs depending on the type of motor vehicle. The distance between a bush and a stopper is set to compensate for unevenness of the respective parts described below.    (a) Unevenness in the mounted positions of the bushes to a body of the motor vehicle    (b) Unevenness in sizes of the bushes    (c) Unevenness in positions of the stopper with respect to the stabilizer
It is desirable that the design distance between the bush and the stopper (hereinafter referred to simply as “control width”) be set to be zero so as to avoid the interference of the stabilizer with other parts by preventing the stabilizer from sideslipping. However, it is not practically possible to set the control width to be zero due to the above unevenness described in (a) to (c). That is, when the control width is set to be much larger, the function of preventing the stabilizer from sideslipping cannot be sufficiently obtained. Furthermore, impact loads act on the stopper when the stabilizer sideslips, whereby the position of the stopper varies. On the other hand, when the control width is small, although the above problem is relieved, it is difficult to mount the stabilizer on the vehicle. In consideration of the above problems, the control width between one side of the bush and the stopper is generally set to be 2 to 3 mm. That is, sideslip of the stabilizer may occur by 2 to 3 mm on one side of the bush due to the unevenness in (a) to (c).
However, even if the control width is set to be the above value, the sideslip distance of the stabilizer increases, and it is difficult to mount the stabilizer to the vehicle.